In recent years, drugs such as pain-killing drugs, steroid formulations, or non-steroid anti-inflammatory drugs are generally used to treat a cartilage disease such as arthritis, and auxiliary materials such as hyaluronic acid, glucosamine, or chondroitin is also used to protect cartilage. However, the above-described drugs serves to non-specifically relieve pain or an inflammatory response, but do not induce regeneration or proliferation of chondrocytes. Also, a chondroprotective agent such as hyaluronic acid aids in maintaining tissues of a cartilage, but does not have an effect on regeneration or proliferation of the chondrocytes.
Therefore, there have been recent attempts to develop a method of replacing damaged cartilage tissue using cell therapy and a tissue engineering technique so as to regenerate the damaged cartilage tissue, for instance, in degenerative arthritis. However, while the cell therapy and tissue engineering requires a large amount of chondrocytes, it is not easy to obtain the chondrocytes in a large amount due to the de-differentiation of the chondrocytes, that is, disappearance of characteristics of the chondrocytes during ex vivo proliferation of the chondrocytes.